It states that you have a fatal error in file c:\Users\Alex\Documents\Unreal Projects\WW1Runner\Intermediate\Source\WW1Runner.Target.cs at line 6, symbol 14. You have to address the error in question. It looks like a symbol name is being declared twice.
I don’t know how to revert back to blueprint-only project, but I will recommend that you make backups in the future. Also, I don’t advice using C++ unless you have some fair amount of experience with it or at least C# or Java.